Polymer groups hydrophobic

The effect of different backbones on ero.sion rates was demonstrated in a study of the homologous poly[ (p-carboxyphenoxy)alkane] series. As the number of methylene groups in the backbone increased from 1 to 6, thus decreasing the reactivity of the anhydride linkage and rendering the polymer more hydrophobic, the erosion rates underwent a decrease of three orders of magnitude (4). 

Absorbance, relative, flocculation of silica hydrosols, 368-73 Acetyl groups, hydrophobic, PVA on PS latex particles, 89 Action-mass relationships, adsorption of soluble polymers, 29 Adsorbance... 

A new process from the paint industry may have application for the suspension coating of pesticide crystals [25]. Low molecular weight water-soluble vinyl polymer chains are synthesized and the process stopped with a terminal vinyl group on each polymer chain. Hydrophobic acrylic monomers are then idded to create the hydrophobic strongly adsorbing backbone polymer. As each water-soluble polymer terminal vinyl group reacts with the growing hydrophobic backbone polymer it becomes inserted like a tooth on a comb. Indeed, these polymer structures are referred to as comb polymers. 

A new class of water soluble cellulosic polymers currently receiving attention Is characterized by structures with hydrophobic moieties. Such polymers exhibit definite surface activity at alr-llquld and liquid-liquid Interfaces. By virtue of their hydrophobic groups, they also exhibit Interesting association characteristics In solution. In this paper, results are presented on the solution and Interfaclal properties of a cationic cellulosic polymer with hydrophobic groups and Its Interactions with conventional surfactants are discussed. 

In this paper, the results on solution and Interfaclal properties of a cationic celluloslcs polymer with hydrophobic groups are presented. Interaction of such polymers with added surfactants can be even more complex than that of "unmodified" polymers. In the past we have reported the results of Interactions of unmodified cationic polymer with various surfactants Investigated using such techniques as surface tension, preclpltatlon-redlssolutlon, viscosity, solubilization, fluorescence, electroklnetlc measurements, SANS,etc.(15-17). Briefly, these results showed that as the concentration of the surfactant Is Increased at constant polymer level significant binding of the surfactant to the polymer occurred leading to marked Increases In the surface activity and viscosity. These systems were able to solubilize water Insoluble materials at surfactant concentrations well below the CMC of polymer-free surfactant solutions. Excess surfactant beyond that required to form stoichiometric complex was found to solubilize this Insoluble complex and Information on the structure of these solubilized systems has been presented. 

QUATRISOFT LM 200,a cationic celluloslc polymer with hydrophobic groups,Is a product of Union Carbide Corporation as Is the cationic celluloslc polymer. Polymer JR. Both have a molecular weight In excess of 100,000. Tergltol NP 10, a nonyl phenol ethoxylate used In this study Is also a product of Union Carbide Corporation. Sodium dodecyl sulfate Is a high purity sample purchased from EM Science Corporation. Pyrene which Is used as a fluorescence probe was obtained from Aldrich Chemicals Co. 

Reversed phase packings Non-polar Reversed phase silicas with n-alkylsilyl groups, reversed phase silicas with hydro-phobic polymer coatings, hydrophobic cross-linked organic polymers, porous carbon Aqueous/organic mobile phases... 

The surface of FPS is characterized by the presence of at least three dominant types of groups hydrophobic hydrocarbon radicals R bonded to silicon atoms, often containing electron-donating or electron-accepting groups residual silanol groups, =Si-OH, where the polymer chain terminates oxygen atoms of siloxane bonds, =Si-0-Si=. Such a variety of the surface character allows for interactions with different sorbates ... 

The solubilization of the HMHEC in the surfactant was attributed to the interactions between surfactant micelles and polymer-bound hydrophobes. The effect of pH on polymer-surfactant solution viscosity was explained in terms of charge effects at the surface of the surfactant micelles. Steiner (13) proposed that at pH levels above or below the isoelectric point, the surfactant has a net charge on the head groups that causes repulsion within a single micelle. This repulsion leads to a relatively open micelle-aqueous phase interface through which polymer-bound hydrophobes can enter and experience stable polymer-surfactant interactions. These interactions anchor the polymer chains in an extended configuration. 

On the other hand, the trans configuration of fumarate ions and rigidity of benzenetetracarboxylate ions do not allow them to interact simultaneously with two surfactant head groups on a single micelle. In the presence of these ions, polymer-bound hydrophobes penetrate more readily into the micelles. In addition, these counterions can potentially bridge two or more micelles, and further stabilize the solution. 

Moisture relations in textile polymers are concerned mostly with the hydrophilic fibers, such as the cellulose groups of cotton, flax, hemp, jute, viscose, modal, and acetates. This is not to say however that the essentially hydrophobic fibers, which fall into the synthetic polymer group (see Fig. 1) have zero moisture imbibition or are totally unaffected by moisture, although this will be true for some of the fibers in this group. 

Polyacrylates as binders consist of copolymers of acrylate and methacrylate esters. Other unsaturated monomers (e.g., styrene and vinyltoluene) may also be incorporated, but usually to a lesser extent. Copolymers formed exclusively from acrylates and/or methacrylates are termed straight acrylics. The comonomers differ as regards the alcohol residues of the ester group, which also allow incorporation of additional functional groups. Choice of suitable monomers allows wide variation of the physical and chemical properties of the resulting polymer. Hydrophilicity, hydrophobic-ity, acid base properties as well as can be adjusted resins containing hydroxyl, amine, epoxy, or isocyanate groups can also be produced. 

Finally, we have considered polymer solutions in good solvents only. For industrial applications, one tends to use more and more water as a solvent. Water soluble polymers have specific properties due to the character of the interactions between monomers in water. Most water soluble polymers, for example, carry ionic charges (they are polyelectrolytes) if the polymers contain hydrophobic groups, they have interesting associating properties. The surface behavior of polyelectrolytes and associating polymers is the subject of intense experimental and theoretical studies [44]. 

In Table 14-1 a Nafion 1 (sulfonated perfluoroalkyl polyanion polymer) membrane is often used since it is a stable cation-exchange polymer able to adsorb cationic compounds easily. A Nafion membrane is composed of hydrophilic columns incorporating anionic sulfonate groups, hydrophobic columns composed of main chains, and interlayer regions between the hydrophilic and hydrophobic columns. When a cationic substrate is adsorbed from an aqueous solution, the adsorbed material is located only in the hydrophilic columns or interlayer regions, so that a real local concentration of... 

The properties of synthetic materials are hugely important to the sportswear industry they are inherently hydrophobic, thermoplastic, and demonstrate high-tensile strength, unlike natural and regenerated fibers that are absorbent but not as strong. Key polymer groups such as polyester and polyamide are conventionally synthesized from non-renewable sources at high cost to the environment. Efforts to find alternative... 

In situ precipitation injectable materials are polymer solutions that precipitate when they come in contact with a non-solvent (physiological fluids) when injected into the body. Usually such polymers are hydrophobic in nature. The polymer solutions are prepared in physiologically tolerant solvents like dimethyl sulfoxide (DMSO) that are also miscible with water. Thus, when the polymer solution is injected into the body, the solvent diffuses and mixes with the physiological fluids while the polymer precipitates out to form the gel as it is not soluble in water. Major examples of this injectable material group include PCL, PLA and PLGA (poly(lactic-co-glycolic) acid) (Coombes et al., 2004, Eliaz and Kost, 2000). 

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